Device and method for filtering messages in a series-type communication system

Abstract

The invention relates to serial type telecommunications networks in which the messages are sent to all the nodes of the network and each comprise an identifier code indicating the content of the message. The invention resides in a device and a method of filtering received messages so as to keep only the messages intended for the node concerned. The method consists of: (a) establishing a list ( 48 ) of the identifier codes (ID) corresponding to messages susceptible of being processed by the microcontroller ( 32, MC), (b) allocating ( 50 ) to each identifier code (ID) of the list an index (FMI), (c) associating ( 44 ), to each message presenting an identifier code of the list, the index (FMI) which has been allocated thereto, (d) associating ( 66 ) to each index (FMI) an address in a memory ( 64 ), and (e) storing each message in the memory ( 64 ) at the address pointed by the index (FMI).

That which is claimed is:  
     
         1 . Device for filtering to a microcontroller ( 32 , MC) messages received in a node of a serial type communications network in which the messages are sent to all the nodes of the network and each comprises an identifier code indicating the content of the message, characterized in that it comprises: 
 means ( 50 ) for associating an index (FMI) to each identifier code (ID) from a list ( 48 ) of identifier codes corresponding to messages susceptible of being processed by the microcontroller ( 32 , MC),    means ( 44 ,  46 ,  52 ) for associating, to each message corresponding to an identifier code of the list, the index (FMI) associated to that identifier code,    means ( 70 ) for storing in a FIFO type memory ( 54 ) the message received and its associated index (FMI), and    means ( 66 ) for associating to each index (FMI) an address in a memory ( 64 ) so as to store each message received at a determined address of the memory ( 64 ).    
     
     
         2 . Device according to  claim 1 , characterized in that the means for associating an index (FMI) to each identifier code (ID) from a list ( 48 ) of identifier codes corresponding to messages susceptible of being processed by the microcontroller ( 32 , MC) comprise a memory ( 48 ,  50 ) containing on the one hand the identifier codes of said list and on the other hand an index (FMI) for each identifier code of said list.  
     
     
         3 . Device according to  claim 1  or  2 , characterized in that the memory containing the identifier codes (ID) of said list and the corresponding indexes (FMI) is a programmable memory.  
     
     
         4 . Device according to  claim 1 ,  2 , or  3 , characterized in that the means for associating, to each message corresponding to an identifier code of said list, the index (FMI) associated to that identifier code comprises: 
 a comparator ( 46 ) for comparing the identifier code of each message with each of the identifier codes of the list contained in the memory ( 48 ) and providing a signal when there is match,    a transfer circuit ( 52 ), controlled by said match signal, for associating to the received message the index (FMI) corresponding to recognized identifier code.    
     
     
         5 . Device according to any one of  claims 1  to  4 , characterized in that the means for associating to each index (FMI) an address in a memory of the microcontroller ( 32 , MC) comprise a programmable memory ( 66 ) which is addressable by the index (FMI).  
     
     
         6 . Method of filtering to a microcontroller ( 32 , MC) messages received in a node of a serial type communications network in which the messages are sent to all the nodes of the network and each comprises an identifier code indicating the content of the message, characterized in that it comprises the following steps consisting of: 
 (a) establishing a list ( 48 ) of the identifier codes (ID) corresponding to messages susceptible of being processed by the microcontroller ( 32 , MC),    (b) allocating ( 55 ) to each identifier code (ID) of the list an index (FMI),    (c) associating ( 44 ), to each message presenting an identifier code of the list, the index (FMI) which has been allocated thereto,    (d) associating ( 66 ) to each index (FMI) an address in a memory ( 64 ), and    (e) storing each message in the memory ( 64 ) at the address pointed by the index (FMI) contained in the message.